Neopentane
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Neopentane
IUPAC name	neopentane
Identifiers
CAS number	[463-82-1]
SMILES	CC(C)(C)C
Properties
Molecular formula	C5H12
Molar mass	72.15 g mol−1
Appearance	colorless gas
Melting point	−18 °C (255 K)
Boiling point	10 °C (283 K)
Thermochemistry
Std enthalpy of formation ΔfHo298	−168 kJ/mol
Std enthalpy of combustion ΔcHo298	−3514 kJ/mol
Standard molar entropy So298	217 J·K−1·mol−1
Hazards
EU classification	Highly flammable (F+) Dangerous for the environment (N)
NFPA 704	4 1 0
R-phrases	R12, R51/53
S-phrases	(S2), S9, S16, S33, S61
Flash point	flammable gas
Related compounds
Related alkanes	Pentane Isopentane
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Neopentane, also called dimethylpropane or 2,2-dimethylpropane, is a double-branched-chain alkane with five carbon atoms. Neopentane is an extremely flammable gas at room temperature and pressure which can condense into a highly volatile liquid on a cold day, in an ice bath, or when compressed to a higher pressure.

Nomenclature

IUPAC nomenclature retains the trivial name neopentane.^[1] Dimethylpropane is the systematic name. The respective substituent numbers (the 2,2-) are unnecessary because there can be no isomers of this molecule with dimethylpropane as part of their names.

A neopentyl substituent or a neopentyl compound has the structure Me₃C-CH₂- for instance neopentyl alcohol.

Isomers

Neopentane is one of three structural isomers with the molecular formula C₅H₁₂, the others being pentane and isopentane.

NMR spectrum

Neopentane has T_d symmetry. As a result, all protons are chemically equivalent leading to a single chemical shift at δ 0.902 in carbon tetrachloride.^[2] This is similar to the silane analog, tetramethylsilane which has a single chemical shift, defined as δ 0 by convention.

Chirally deuterated neopentane ([2H1,2H2,2H3]-neopentane) is an interesting molecule. The neopentane is rendered chiral by the isotopic substitution of hydrogen . Its chirality arises solely by the mass distribution of its nuclei, while its electron distribution is completely achiral.

References

The references used in this article may be clearer with a different or consistent style of citation, footnoting, or external linking. This article has been tagged since September 2007.

• Panico, R.; & Powell, W. H. (Eds.) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-632-03488-2. 

External links

• European Chemicals Bureau
• NIST Chemistry WebBook
• IUPAC Nomenclature of Organic Chemistry (online version of the "Blue Book")
• Molview from bluerhinos.co.uk See Neopentane in 3D